Thermal transfer sheet

Abstract

A co-winding type thermal transfer sheet is constituted by forming on one surface side of a substrate film a heat-fusible ink layer comprising a pigment and a particulate binder, and causing a tracing paper to be peelably bonded onto the heat-fusible ink layer by the medium of an adhesive layer. The thus constituted co-winding type thermal transfer sheet is capable of providing an original image which can be reproduced by use of a blueprint process so as to provide blueprint images having a high precision and a high contrast. In addition, a co-winding type thermal transfer sheet may also be constituted by forming a heat-fusible ink layer on one surface side of a substrate film and causing a transparent resin sheet to be peelably bonded onto the heat-fusible ink layer by the medium of an adhesive layer containing a cross-linking agent. The thus constituted co-winding type thermal transfer sheet is capable of providing an image excellent in wear resistance on the transparent resin sheet. The transparent resin sheet after the image formation may be used as an OHP (overhead projector) sheet without contaminating the sheet having no liquid absorbing property.

What is claimed is: 
     
       1. A thermal transfer sheet, comprising: a substrate sheet, one side surface of which is provided with a heat-fusible ink layer, and   a thermal color-developing paper which is peelably bonded to the heat-fusible ink layer by the medium of an adhesive layer comprising adhesive particles.   
     
     
       2. A thermal transfer sheet according to claim 1, wherein the adhesive layer comprises adhesive particles having a low glass transition temperature, resin particles having a high glass transition temperature, and wax particles. 
     
     
       3. A thermal transfer sheet according to claim 2, wherein the weight ratio among the adhesive particles, the resin particles and the wax particles constituting the adhesive layer is (1 to 3):(0 to 2):(1 to 3). 
     
     
       4. A thermal transfer sheet according to claim 1, wherein the adhesive particles have a glass transition temperature of -90° C. to -60° C., and the resin particles have a glass transition temperature of 60° C. or higher. 
     
     
       5. A thermal transfer sheet according to claim 1, wherein the adhesive layer has a thickness in the range of 0.2 to 20 μm. 
     
     
       6. A thermal transfer sheet according to claim 1, wherein the adhesive layer is formed from a dispersion comprising the adhesive particles, the resin particles and the wax particles. 
     
     
       7. A thermal transfer sheet according to claim 1, wherein the heat-fusible ink layer has a transfer temperature which is higher than the color-developing temperature of the thermal color-developing paper. 
     
     
       8. A thermal transfer sheet according to claim 1, wherein the heat-fusible ink layer has a transfer temperature which is lower than the color-developing temperature of the thermal color-developing paper. 
     
     
       9. A thermal transfer sheet according to claim 1, wherein the thermal color-developing paper has a surface which is to be subjected to a printing operation and has been provided with a printed image in advance. 
     
     
       10. A thermal transfer sheet according to claim 1, wherein the thermal color-developing paper has been subjected to an antistatic treatment.